MB39A113 Datasheet, PDF (35/51 Pages) Fujitsu Component Limited. – ASSP for Power Supply Applications (Secondary Battery)

MB39A113
Example) Using the 20SVP22M
Rated voltage = 20 V, ESR = 60 mΩ, maximum allowable ripple current = 1450 mArms
Equivalent series resistance
16.8 V output
∆Vo
ESR ≤
∆IL
1
−
2πfCL
0.168
1
≤
−
1.22
2π × 300 × 10³ × 22 × 10^−6
≤ 114 mΩ
12.6 V output
∆Vo
ESR ≤
−
∆IL
0.126
≤
−
1.2
≤ 80 mΩ
1
2πfCL
1
2π × 300 × 10³ × 22 × 10^−6
Capacitance value
16.8 V output
∆IL
CL ≥
2πf (∆Vo−∆IL × ESR)
1.22
≥
2π × 300 × 10³ × (0.168−1.22 × 0.06)
≥ 6.8 µF
12.6 V output
∆IL
CL ≥
2πf (∆Vo−∆IL × ESR)
1.2
≥
2π × 300 × 10³ × (0.126−1.2 × 0.06)
≥ 11.8 µF
Ripple current
16.8 V output
(VIN−Vo) tON
ICLrms ≥
2√3L
(25−16.8) × 0.672
≥
2√3 × 15 × 10^−6 × 300 × 10³
≥ 707 mArms
12.6 V output
(VIN−Vo) tON
ICLrms ≥
2√3L
(22−12.6) × 0.572
≥
2√3 × 15 × 10^−6 × 300 × 10³
≥ 690 mArms
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